Like other members of its family, it is viviparous with females giving birth to two to six pups in estuarine nursery areas every other year.

The finetooth shark was originally described as Carcharias (Aprionodon) isodon by French zoologist Achille Valenciennes, in Müller and Henle's 1839 Systematische Beschreibung der Plagiostomen.

[4] As is the case for most Carcharhinus species, attempts to analyze the finetooth shark's phylogenetic relationships have yielded variable results.

Each tooth is small and needle-like, with a narrow central cusp and smooth to minutely serrated edges.

The five pairs of gill slits are long, measuring about half the length of the dorsal fin base.

Living finetooth sharks are a distinctive dark bluish-gray above and white below, with a faint pale stripe on the flanks and no prominent fin markings.

In Central and South American waters, it is rare, but may occur more widely than presently known, having been reported off Trinidad and Guyana, infrequently from the Caribbean Sea, and off southern Brazil from São Paulo to Santa Catarina.

[1][8] Old records exist of this species in the eastern Atlantic off Senegal and Guinea-Bissau, but these likely represent misidentifications of spinner sharks (C.

[8] Historically, it was known to venture into rivers in the Gulf Coastal Plain of Texas, though most of paths into this area are now blocked by dams.

[9] The northwestern Atlantic population of this species is strongly migratory: juveniles, followed by adults, arrive off South Carolina from late March to early May, when the water temperature rises above 20 °C (68 °F).

[2] This energetic, fast-moving predator feeds mainly on small bony fishes, often entering the surf zone during the day to hunt.

Other known prey species include spot croaker (Leiostomus xanthurus), Spanish mackerel (Scomberomorus maculatus), mullet (Mugil spp.

The semen exuded by the male congeals into a large, spongy mass inside the female's uterus, in which the individual spermatozoa are embedded.

[1] Fishing for this species in U.S. waters is regulated by the National Marine Fisheries Service 1993 Fisheries Management Plan for Atlantic and Gulf of Mexico sharks; it is classified as a "small coastal shark" for the purposes of commercial quotas and recreational bag limits.

Concern existsfor this species in South America, where its numbers seem naturally low and it is potentially under heavy pressure by widespread, intensive coastal fisheries.